Measuring a frame for straightness

[George Ryals]

Rob, I think it would be worth a phone call to G.M.D. Computrack to see if they have the specs on your frame and could measure it on their machine.

Scranton - North American Warhorse

1000 Dunham Dr.
Dunmore, PA 18512
Mike: 866-222-2453 Ext. 211
gmdcomputrack@nawarhorse.com

[Deleted User 61]

Oh! I could throw it in my car and drive it over, and stop and see my daughter in Williamsport!

[vanzen]

Agree with GSPD –

1) the frame is not likely to bend there, and
2) sure you got those spacers in correct ?

Could the SA be bent ?
A much more likely scenario than the lower frame.

The clutch arm interference that you have described has me baffled, still.
But I would not assume it to be a result of the accident ... or a fault of the frame.

[Roy Gavin]

Time moves on, modern frame shops have a computerised measuring jig which indexes of the headstock bearings and a programme that has the vital, err, coordiates of almost every frame ever made.
Everything made has production tolerances, and a welded structure like a frame will have a reasonable allowance for error, you probably wouldnt notice 10mm anyway.

I read somewhere that airhead frames tend to bend upwards at the rear engine mount, makes sense if you compare them with the frame the were copied from.

[Deleted User 61]

Hello,

It is a new day.

I checked my parts catalog. There are 4 spacers and they all have the same part #.
I checked the bike again. 4 spacers, between the engine casting and the frame.

[Deleted User 61]

For what it is worth, here is a video of the action, both from top & bottom.

Not much to see.

http://www.youtube.com/watch?v=tH1NVdZdkbc

[gspd]

Is it only rubbing when pulled all the way forward?
If so, your lever is too far forward.
Turn the handlebar cable adjuster IN to give it lots of slack and take out said slack by screwing in the adjuster on the back of the actuating arm. There is a lock nut holding the adjuster in place.
I can't see the actual pivot on your vid, but the angle looks like it will be better if you move the arm back.

In a perfect world the arm should be perpendicular to the pushrod (parallel to the case) at mid hand lever travel.
That's where the clutch will have it's lightest feel, and the moving components of the linkage will be the least stressed.
Changing clutch parts will affect this adjustment, maybe that's why it is now rubbing.
Did you swap any parts in there? clutch, clutch pushrod and release bearing, flywheel, etc

When all is said and done, adjust the free-play at the hand lever to about 1mm.
The hand lever will tighten up as the clutch breaks in and/or wears out, so check that it still has free-play periodically.
For that, use only the cable adjuster at the handlebar.
There should be no further adjustments needed at the actuating arm once it is set up properly.

[gspd]

Rob said:
My original post back in March:
You don't seem to have participated!

I re-read most of it today.
Boertjie nailed it about 10 posts down.
I thought you tried that and the lever still rubbed.
after that I had nothing to add to the frame discussion.
all the bases were covered.

I have a pitbull's obsessiveness when a problem is "unfixable', but rapidly lose interest once it's fixed.

[Deleted User 61]

Well, I guess I will play with the adjustments and see what happens.

Easier than building a new bike.

[gspd]

Remove the spring and slack off the cable adjuster while adjusting the arm.
The lock nut is 13mm, the adjuster is 10mm. it probably needs about 1/2 to 3/4 turns in.

Try your best to set it up so once everything is locked down, the arm is straight when the clutch lever is pulled in half way.
A bit further back is OK if that's what's absolutely needed so the arm does not rub.